| Ultra-wideband (UWB) radio-frequency technique is a kind of wireless communicationtechnology, which is far more promising in the application of short distance and high speed. It hasaroused widespread concern because of its various advantages such as its strong abilities incounteracting the multi-path effect, high transfer rate, low power, high security, shareingbandwidth with pre-existing RF system and so on. UWB-over-Fiber technology came up based onoptical fiber in order to improve the weakness of short effective transmission distance of UWBsignals because of its low transmitted power. How to modulate UWB signals to the continuouslight and transmit in fiber optics with low loss has been a hot topic for experts and researchers. Onthe basis of previous studies, several modulation proposals base on Lithium NiobateMzch-Zehnder Modulator are proposed. The specific steps are as follows:(1) The background and significance of the research in UWB signals is introduced. Thestatus of the research in generation and modulation technology of the UWB signals at home andabroad is summarized.(2) A modulation scheme on ultra-wideband on-off keying (OOK) based on a Lithium NiobateMach-Zehnder modulator is proposed. The theoretical model of this scheme is analysed. By usingthe softwares of Matlab and Optisystem7.0, the impact of pulse width, source power, sourcewavelength and modulation rate on OOK signal and the transmission characteristics of OOK signalin fiber are investigated.(3) A modulation scheme of ultra-wideband pulse amplitude (PAM) based on a LithiumNiobate Mach-Zehnder modulator is proposed. By using the software of Optisystem7.0, both theimpact of pulse width, source power, source wavelength and modulation rate on the PAM signal andthe transmission characteristics of PAM signal in fiber are investigated.(4) A modulation scheme of ultra-wideband pulse shape (PSM) based on two Lithium NiobateMach-Zehnder modulators is proposed. By using the software of Optisystem7.0, both the impact ofpulse width, source power, source wavelength and modulation rate on the PSM signal and thetransmission characteristics of PSM signal in fiber are investigated.(5) A new UWB pulse shape modulation based on Lithium Niobate Mach-Zehnder modulatorand electro-absorption modulator (EAM) is presented. By using the software of Optisystem7.0,both the impact of pulse width, source power, source wavelength and modulation rate on the PSM signal and the transmission characteristics of PSM signal are investigated. Finally, the scheme issimplified by optimizing. |
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